Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1998-10-02
2002-10-08
Mengistu, Amare (Department: 2673)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S077000, C349S042000
Reexamination Certificate
active
06462722
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to a display apparatus in which a current-driven light-emitting device, such as an organic electro luminescence (hereinafter referred to as “EL”) display device, are driven by using thin-film transistors. More particularly, the invention relates to a current-driven light-emitting display apparatus driven by thin-film-transistors, which realizes the suppression of deterioration with time, and to a method of producing the same.
2. Description of Related Art
The inventor of this invention carefully examined organic EL display devices driven by thin-film transistors, and ascertained the following facts.
(1) In an organic EL display device driven by thin-film transistors, since the organic EL display device is a direct-current device, direct current also runs through thin-film transistors, which are connected in series to the EL device, for the purpose of controlling it.
(2) Thin-film transistors are classified into an n-channel type and a p-channel type. These types differ extremely in the manner in which deterioration with time occurs.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to suppress the deterioration with time of thin-film transistors in a current luminescent device driven by the thin-film transistors.
(1) In the present invention, there is provided a current-driven light-emitting display apparatus comprising a plurality of scanning lines and a plurality of data lines, thin-film transistors and current luminescent devices being formed in positions corresponding to each of the intersections of the scanning lines and the data lines, wherein at least one of the thin-film transistors is a p-channel type thin-film transistor.
It is possible to suppress the deterioration with time of a thin-film transistor with this apparatus.
(2) In the present invention, there is provided a current-driven light-emitting display apparatus in which a plurality of scanning lines, a plurality of data lines, common electrodes, and opposite electrodes are formed, with first thin-film transistors being formed in positions corresponding to the intersections of the scanning lines and the data lines, second thin-film transistors, holding capacitors, pixel electrodes, and current luminescent elements, the first thin-film transistors controlling conductivity between the data lines and the holding capacitors by the potentials of the scanning lines, the second thin-film transistors controlling conductivity between the common electrodes and the pixel electrodes by the potentials of the holding capacitors, to thereby control the current which flows through the current luminescent elements provided between the pixel electrodes and the opposite electrodes wherein the second thin-film transistors are p-channel type thin-film transistors.
(3) In the present invention, there is provided a current-driven light-emitting display apparatus according to (1) or (2), further comprising a driving circuit for driving the current luminescent element, the driving circuit is comprised of the plurality of scanning lines, the plurality of data lines, the thin-film transistors, and the current luminescent elements, which are disposed on the substrate, wherein the p-channel type thin-film transistors are formed in the same step as the thin-film transistors in the driving circuits.
(4) In the current-driven light-emitting display apparatus according to any one of (1) to (3), the thin-film transistors are polysilicon thin-film transistors.
(5) The invention provides a current-driven light-emitting display apparatus according to (3), wherein the drive circuits comprise complementary type thin-film transistors, the first thin-film transistors are formed in the same step as n-channel type thin-film transistors in the driving circuits, and the second thin-film transistors are formed in the same step as the p-channel type thin-film transistors in the driving circuits.
According to (5), it is possible to provide a current-driven light-emitting display apparatus, which exhibits high performance with no deterioration with time, without increasing the number of steps for producing the apparatus.
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Itoh Tomoyuki
Kimura Mutsumi
Mengistu Amare
Seiko Epson Corporation
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